Lake Maxinkiickee, Physical and Biological Survey 161 



The Diatoms, Etc. 



One of the first things to strilve the attention of any one inter- 

 ested in the flora of the lake, especially if he happen to visit it 

 during the cooler season of the year, is the great abundance and 

 variety of diatoms. The collector of the filamentous algje, such as 

 Cladophora or Spirogyra or of the various Characese, will find his 

 catches overgrown with diatoms, and one of our earliest botanical 

 notes concering the botany of the lake was, "The charas of Lost 

 Lake are thickly covered with brown, boat-shaped diatoms." In 

 the autumn of 1901 it was noted that the bottom of Aubeenaubee 

 Creek was covered with a brown diatomaceous scum. 



The diatoms prefer cold water and in the winter they thrive 

 luxuriantly in the lake, forming a thick, gelatinous coating over the 

 weeds. 



During the summer, floating diatoms are not especially abund- 

 ant in the lake, and do not form a conspicuous part of plankton 

 obtained by surface-towing, this being composed mostly of blue- 

 green algsB, or entomostraca, or both. During the colder portions 

 of the year, in early spring and late autumn, that is in early April 

 and late September, the free floating diatoms are much more abund- 

 ant, largely taking the place of the blue-green algte. On some days 

 the towing in deep water would be chiefly entomostracan, re- 

 sembling a soft, jelly mass, on other days they would consist 

 chiefly of diatoms, and would have a harsh feeling and bristly 

 appearance. For example, a haul of April 29 was nearly all 

 diatomaceous. During the autumn of 1906, after towing all Au- 

 gust, September and October, and getting little vegetable plankton 

 but blue-green algae, a haul on November 12 contained an abund- 

 ance of diatoms. It is unfortunate that plankton was not taken by 

 means of a pump or other device, during the winter ; the probabil- 

 ities are that the plant-plankton would have been almost all or 

 entirely diatomaceous. 



The various diatom gatherings were submitted to Dr. Albert 

 Mann of the U. S. Department of Agriculture for his identification. 

 The following are his notes : 



"Sample No. 1. [Cladophoi-a glomerata growing on submerged 

 rocks, November 17, 1904] . Cocconeis pedicidus E ; Gomphonema 

 olivaceum E ; Cymbella cymbiformis E ; Cymbella macidata Kuetz- 

 ing; Cymbella naviculifornns Auerwald (variety) ; Cymatopleura 

 elliptica W. S., Cymatopleura solea W. S., Epithemia argus Kuetz- 

 ing; Epithem,ia gibba Kuetzing; Navicula reinhardti Grun ; Navi- 

 cula gastrwn Ehrenberg; Synedra obtusa W. S., Synedra radians 

 W. S. (variety). 



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